Pneumatic hammer.



W. BAXTER, JR.

PNEUMATIC HAMMER. APPLICATION YILED MAR. 12, 1906.

Patented Oct. 5, 1909.

INVENTOE A TTOHNE Y6.

To all whom itmay concern:

UNITED. srarns Parana onnrcn.

WILLIAM BAXTER, JR, or JERSEY-CITY, new JERSEY.

PNEUMATIC HAMMER.

Be it known that I, WILLIAM BAXTER, J12, a citizen of the United States,residing in Jersey City, in the-eounty of Hudson and State of New Jerse'y, have invented certain new and useful Improvements in PneumaticHammers, of which the following is :1V specification;

The present invention relates to pneu matic hammers or similarreciprocating tools, and the object of the iiivei'ition is to provideimproved means for regulating the force of the blow and the velocity ofthe hammer. I

Another object 9i? the invention is to so construct the actuating'valvethat it will. at the same time act as a throttle valve. Other andfurther objects will appear from the following specification and will bemore particularly pointed out in the annexed claims.

In the accompanying drawing-Figure 1 is a longitudinal section throughthe entire hammer; Fig. 2 is a section through-the valve chamber,' onthe line a-a, Fig. l, the valve and the parts cooperating therewithbeing removec; Fig. 3 is a section on the line b-b, Fig. 1,.with thevalve removed;

Fig. 4 is a section on the line cc, Fig. 1; Fig. 5 1s a bottom view ofthe cylinder cap; Fig. 6 1s a side vlew of Fig. 5; Fig. 7 1s a top Viewof Fig.5; Fig. 8 is a side view of the actuating valve, partlyeinsection; Fig.- 9 shows one of the stop plungers, and F 1g. 10 shows amodified form 01' plunger and one of the valve chamber heads.

1 is a casing which is formed in the shape of a handle at the upper end,and at the lower end is shaped to receive the valve and the upper end ofthe working cylinder.

2 and 3 represent the working cylinder 'which preferably is made intwo'parts secured'together by screws 58, to simplify the construction ofthe 'ports 30 and 31, but the cylinder may be made solid and holes maybe drilled therein to form the ports.

4 istheplunger and 5 is the combined actuating and throttle valve. Thevalve chamber is nfieferab ly provided with. a lining 6 to increase thedurability of the tool.

7 and 8 are valve chan'iber heads, and 9 and 10 are stop plunger-shaving stems 59 and enlarged inner ends 37 provided to limit themovement of the valve in either direction. i

Specification of Letters Patent. i Application filed March 12,

12 is the lower head of the working cylin- Iatented Oct. 5, 1909.

1906. Serial No. 305,635.

der, and 13 is thesha'nk of the tool which is driven forward by thelower end 51 of the plunger 4:; i

14- is the inlet through which com'n'essed .air passes to the tool,.15and 16 are levers through which the operator moves the plunger 10,-and17, 18, are levers through which he moves the plunger 9, all theselevers being pivoted on studs 19.

g 20 and- 21 are recesses in the sides of 1, in which the ends of 0 and10 are located so as to be protected against external injury.

22 is the large end of the valve chamber and is the .small end which isprovided with an abutment for the head 8. I

24-, and 26, are ports provided in the valve chamber and 11 is thecylinder cap which isprovided with ports 27 and 28, in its upper side.

' 29 is a projection on the lower side of the cap 11 which serves tomake a tight joint against the end of the cylinder, and also to "form aport 54.

30 and 31 are ports'in the cylinder, thefirst connecting the lower end52 with the ported, and the latter connecting an annular port 34surrouiuling the cylinder with a port 57 provided in the wall of thecylinder.

32 is an annular port surrounding the cap 11 and connecting the port 27with the cham- 'ber into which the inlet 14 opens.

and 36 are ports that serve to connect the port 3 1 with a space 43between the head 7 and the left end of the valve 5.

37, 37 are enlarged ends of the stop plunger-s t), 10 that fit closeenough into the depressions in the enlls of the valve to act as cushionsand thus prevent the valve from strikingviolently against them, butthey, do not fit air tight.

38, 3t) and 40 are the piston portions of the valve 5, whiclnareconnected with each other by necks 41,41. The portions 38 and '39 are ofthe same diameter while the portion 10 is of less diameter than theother portions.

42 isa small portthat connects the port; 28 with the space 43, and 44 isan exhaust port that connects with the port 24. when the .valve movesfar enough to the left. 415 are holes through cap 11 that connect theport 28 with the port 54:. r

46 are pins and 47 are holes n'ovided to hold the cap 11 in a fixedposition with relation to the casing 1. l r 48 is acylindricaldepression in the upper The operation of the hammer is as follows: Ifthe levers 15, 16 and 17, 18 are .in

the position shown in Fig' 1, and the inlet 14 is connected with asource of.compressed air, the hammer will use the maximum ainount ofa-irand will make the maximum number of strokes in unit time and strikethe maximum blow. Thelevers "17, 18 are nor mally in the-position shownin Fig. 1, while the levers 15, 16 are held in this position by thethumb of the operator andagainst the action of a spring 55 The stop'plungers 9-10 are forced outwardly against levers 18 and 115respectively by spiral springs, surrounding the stems 59 as clearlyshown. When it is desired to stop the tool, the operator releases hishold on the lever 16 and the outer end of the lever is thrown upwardbythe spring '55, and this movement swings the lower end of the lever 15to the right until the enlarged end 37 of the plungei lt) lies against[the valve 5 and prevents the movement of the valve. The compressed aircoming from the source 14 passes through the chamber 33 and the ports32, 27 and 26 to the space between the pistons 39and of the valve, andas the former is larger than thelatte'r, there is an excess of-pressureacting to move the valve to the left, but it cannot move until theoperator depresses the lever 16 If the lever 16 is depressed to theposition shown in'Fig. 1, the valve 5 will be free toiniove to the leftuntil it strikes the enlargedend 37 of the plunger 10. Then it so moves,valve piston 39 will pass to the left and thus open connection betweenthe ports 25 and 26, andthe compressed air will pass to the upper, endof the cylinder. If the plunger 4 is at the top of the cylinder, it willbe forced down to the'position shown'in Fig. 1, by the compressed air.As soon as it is far enough down to uncover the port 57, the air willpass to the port 31, thence through the ports 34, 35 and 36 to the space43between. the head 7 and the valve piston 38. The pressure .on the leftside of the piston 38 will now balance the pressure on the right side ofthe piston 39 and the unbalanced pressure against the left side of thepiston 40 will, therefore, force the valve to the right to the positionshown in Fig. 1 When the valve reaches this position, the compressed airin the upper end of the cylinder will pass through the ports 25,24, 28

and 30 tdthe'space 52 at; the lower end of. .the cylinder, and 'ift'here -i's '-air ,tight con nection between the shank 13 and thecylinrler end, the pressure'will force thepluniger upper en as the end50 is larger than the 4. upwardy,

. When the plunger 4 has been forced nearly to the uppermost positionthe p lower edge of the head -50 uncovers the ex-' haust port53 andpermits the air to escape from the cylinder. port 53 is connected withthe port 57,

At the same time, the

through the neck 49, so that the compressed air in the space 43 is alsoexhausted and thus the pressure is relieved at this end of 7 5 thevalve, and the pressure on the right side.

of the piston 38 is unbalanced so that the valve is now moved totheleft, readvto repeat the cycle.

Fromvthe above derstood that if the valve. is not perfectly air tight,the compressed air which has passed to the space 43through the port 57,wi'll soon leakout after the portv 57 .is covered by theplunger 4 on:the return stroke, hence the valve would be forced over to the leftbefore description, it will be nn the plunger 4 reached the upperposition.

The result ofthis would be that the full stroke of the plunger 4wouldwnot be obtained. To prevent this occurrence, the small port 42- isprovided which connects the port 28 andthe space 43 so that'the pressurein the space 43 may be maintained after the covered by the plunger 4 onthe port 57 is It will also be seen that if'the upstroke.

valve piston 40 does not fit perfectly, the

space between the piston 40, and the head 8 would gradually be filledwith compressedair and then the valve would not operate; To prevent thistrouble, the stop plunger '9 does not fit tightly against the head 8,but portions are cut awa in the head 8 at the upper side of the'p ungei9, as shown in Fig. 1.

The amount of air that passes to the working cylinder, determines theforce with which the plunger 4 is driven forwardly, that is,

the force of the blow upon the shank 13.

The amount of air is controlled by/theextent to whichuthe'port 25 isuncovered-by the valve when it moves. to the left ndthis movement of thevalve isicontrolle by the positionof the stop plunger 10; hence, the]force of the bl w can be increasedor. de;

creased by the extent to which the operator depresses lever 16. Thusthrough the proper manipulation oflever "16, the force of the blowsstruck by the hammer can be regulated. Y Q

. The velocity at which the plunger 4, will move on the backward stroke,that is;-f1 .om

the head 12 to the cap 11, dependson the velocity with which thecompressed air can, pass from the upper tOdlliGfQWQI end of thecylinder, and this velocity will depend upon the extent to which theport 25 is uncovered by the valve 5 when the valve moves to the right.It will be seen that if the operator; raises the lever 1. the stopplunger-9 will be forced to,,the 'leftandt'he opemngof the port 25 willbe reduced, hence, the more the lever -171s raised the more the )ort 25will be closed, and the slower the velocity of the,

to be absorbed by the inertia of the tool.

The mon'ientun'i on the forward stroke does not, jar the tool becauseitis all expended upon the shank 13 of the working tool. To reduce thejarring of the hammer to a minimum, it is necessary to reduce thevelocity of the plunger at on the backward stroke as much aspermissible. To make the blow of the plunger 1 upon the shank 3 ase'l'l'ective as possible, it is necessary to let the compressed air havefree access to the cylinder of the down stroke. or fOIH'tU'Cl stroke,and

to accomplish this, it is necessary that the valve opens the port 25 aswide as practicableto allow the requiredamount of air to pass into thecylinder. It the movennnt ot the value 5 were controlled entirely by theposition of the plunger 10, it is evident that the rapidity of thestrokes would vary with the forceeot' the blows struck by the pltuigcr4', both increasing and decreasing together. By providingthe-stopplunger l), the rapidity and-the force Ofliljttf? blows can be variedindependently; thus it it is desired to strike with the maximum force.but with a long interval between the blows, the result can beaccomplished Lrv depressing the lever 15 to the lowestpositron, whichwill produce the maximum blow, and by drawing the lever 17, upward whichwill reduce the rapidity of the strokes.

.Tn reduce the vibration of the tool as lIltlClLZh-S possible, theextent to which the port- 21") is openedwhen the parts are in thepositionshown in the drawing, that is when the ports and 25 areconnected, is determined experimentally, the opening being graduallyincreascd-uiitil the jarring be comes all that is considered admissible.For

I any rapidity of strokes below this limit-,the

vibration will be decreased. If it isdesired to arrange the tool so thatthe movement ot the plunger 4 may be actually stopped by moving thelever 17, the levers 17 and 18 are arranged in such a manner that theycan move the plunger 9 so far to the leftthat the valvewill not open theport when moved 'to the right; hence, the air. in the upper end I of thecylinder cannot pass to the lower end.

1 If it is not desired to have the tool operate in this way, but merelyto have the move ment of the lever 17 acting to reduce the rapidity ofthe strokes, a suitable stop is provided to limit the movement of lever18.

The simplest way to provide such a stop is to make the distance betweenthe upper end of the lever 18, and the handle 1 such that when the leverstrikes the handle, the rapidity of the strokes is reduced to minimum.

From the foregoing explanations, t Wlll be seen that till my improvedhammer, it

is possible ,to strike the hardest blow with When the levers 17, and 18,are provided, I

the operator can vary the rapidity of the strokes at will; but in manycases this is not necessary, itv being sullicient'to be able to set thetool to operate at a given velocity. In

such case, the levers 17, 18, are discarded and the stop plunger 9 andthe head 8 are made as shown 'in Fi 10 so that the plunger may be set inany desired position. To hold it securely in this position, a check nut'61 is provided.

The office of the port 44 to provide an outlet for the-air from thespace 52 under the plunger. when the latter on the forward stroke hasmoved far enough .tomake the head 50 cover the port 53. After this portis covered the air escapes through the port 30 and the valve chamber tothe exhaust port .44. I

It will be noticed particularly that the valve 5 plays the double par-tot an actuating valve and a throttle valve, but it is to be understoodthat my invention is notrestricted is used.

It will be easily understood that the the head 7 in the position inwhich it is shown in Fig. 1, or it could. be made integral withthe head,and the compressed air could be admitted to the tool through any of thevarious forms of throttle valves commonly used, such valve beingoperated by the lever 16, or in any-other desired manner. Thus a simplestopcock in the inlet 1-1 could be made to answer the purpose of athrottle.

In order that a pneumatic hammer of this type may deliver the hardestblow possible at the available pressure of the compressed air,'it isnecessary that the construction be such thatthe loss of pressure betweenthe supply pipe and the cylinder be reduced to minimum. As the movementof the plunger st on the forward stroke is resisted only by the smallfrictional resistance and a very slight back pressure, it willaccelerate its 've-. locity very rapidly, and thus reduce'the pressurematerially if the ports connecting the valve withthe cylinder are long.In

through the valve is reduced, to give ighter to this arrangement,because the valve 5 in 'plunger 10 could be pern'ianently secured toblows; If the valve is placed as close to the cylinder as possible, asin Fig. 1, the presair may be throttlcd, because the clearance spaceWithin the valve chamber and the ports connecting with the cylinder, isso small that it can be filled without making a material reduction inthe pressure in the port'26, and this pressure is the same as that atthe inlet 14, owing to the large size of the connecting passages 32, 33and 27.

Having described my invention, what I- claim as new is:

l. A pneumatic tool having an actuatingvalve operated by, the compressedair in a continuously automatic manner and means.

movable independently of the valve controlling said valve whereby it isadapted to perform the function of athrottlihg valve. 2. In a pneumatictool, the combination with the reciprocating plunger, of an actuat ingvalve operated by the compressed air in' a ,continuously automaticmanner, and arranged to vary the velocity of the plun er during thereturn stroke, and means whereby the valve is adapted to perform thefunction of a. throttling valve.

3. In a pneumatic tool, the combination 1 with the reciprocatingplunger, of an actuattling valve.

ing valve operated by the compressed air in' a continuously automaticmanner and adapt- .ed to control the velocity of the plunger on thereturn stroke, resiliently mounted means for varying the stroke of saidvalve while in action, and means whereby the valve is adapted to performthe function t. In a pneumatic hammer, the combination with the workingcyllnder, of an actuatmg valve arranged to admit compressed air to theupper end of the cylinder and to permit the transfer of such air fromthe upper to the lower end of the cylinder, and means whereby the valveis adapted to per form the function of a throttling valve.

5. In a pneumatic hammer, the combination with the Working cylinder, ofacombined throttle and actuating valve arranged to admit compressed. airto the upper end of thecylinder and to transfer such air from the upperto the lower end of the cylinder,

and the valve controlling the rateof flow during the transfer, andresiliently-mounted means movable relatively to the valve and under thecontrol of the operator to vary the the hammer. 4

.6. In a pneumatic hammer having a reciprocating operating valveactuated by, the compressed air, means movable relatively to the valvefor controlling the travel of the 4 action of the valve during theoperation of 'valve in such manner as to permit the thro n 'of a throt;

sure acting on the plunger 5, at the beginning of the stroke, will .benearly the full pressure, no matter how much the supply of.

. tion of. the

establishing communication to be modified at will during the operationof the hammer.

7. A portable pneumatic hammer provided with an actuating valve placeddirectly above; the cylinder end, said valve;

being reciprocated continuously by the pressure fluid while the tool isin action; and means to enable the valve to act as a throttle when thetool is not in action.

8. In a pneumatic hammer having a re ciprocating operating valveactuated by the compressed air, means actuated independ ently of thevalve for controlling the movement of the valve in either directionindependently while the hammer is at work.

9.111 a portable pneumatic hammer, a

working cylinder and striking plunger; an

operating valve placed directly above the.

end of the cylinder, said valve being adapt-- ed to reciprocatecontinuously under the ac- -working cylinder and striking plunger; an

operating valve located directly above the cylinder end, said valvebeing reciprocated continuously by the pressure fluid while the ressurefluid; means operable tool is in action, means acting independently. I

of the valve for instantly varying the throw of the valve in eitherdirection while the tool is in action, said means enabling the valve toact as a throttle when the tool is not in action. I

12f In a pneumatic hamm'er, the combination with the working cylinder,of a reciprocating. operating valve actuated by' thecompressed air andadapted to control the flow of airfrom one end of the cylinder totheother, and means acting independently. of the valve for 'varying the.movement of the valve during the movement thereof.

13. A pneumatic'hammer, having a working cylinder, an automaticallyactuated valv directly above the cylinder; and means actuatedindependently of the valve, here. by said valve is adapted to performthe functions of a throttling valve. 14. In a compressed air actuatedder, the plunger, and passages communicating with the upper end of thecylinder and betweenends of the cylinder; and means emulated inhammer,the combmation wlth a working cylintion. one of said stops being furtheradapted to start and stop the hai'nmer.

16. I11 a pneumatic hammer, having acontinumisly automatic actuatingvalve, stops adapted to slide axially in'the direction of movement, ofthe valve, and means whereby the stops are held in any desired,

position subject to the will of the operator.

l7. In'a pneumatic hammer having a con- 'tinuonslyautomatic actuatingvalve, stops adapted to slide axially in the direction of.

movement of the valve, means whereby the stops are heldln any desiredposition so as to l1m1t the throw of the valve in either direction, andmeans for adjusting the position of one of the stops.

18. In a pneumatic hammer having a continuously automatic actuatingvalve, stops adapted to slide -resiliently in the direction of movementof the *alve, means whereby the stops are heldin any desired position soas to limit the throw of the valve in either lirection, and means forvarying the positions of said stops independently.

19. In a pneumatic hammer the comblnation of a working cylinder, a valvechamher to which the compressed air has access,-

a continuously acting pressure-actuated valve within said valve chamber,controlling the admission of pressure medium to the [Working cylinder,and means actuated at will independently .of the valve defining themovement of said valve and causing the valve to throttle the flow ofpressure medium. v

20. A pneumatic hammer provided with two actuating levers arranged tobeoperated by the fingers of the operator, one of said levers acting tocontrol the force of. .the blows struck by the hammer, the other of saidlevers acting 'to control the rapidity of the blows, and stops moved bysaid levers,

arranged to slide freely in the pathof the actuating valve to limit thethrow of the valve in either direction.

21. In a portable pneumatic hammer having an operating'valve that isreeiprocated by the pressure fluid; means for varying the throw of thevalve in either direction, said means being constructed and arranged tobe operated by the fingers on that hand of the operator that'grasps thehandle of the tool,

and comprising means adapting the throw of the valve in either directionto be instantaneously varied independently of the throw in the otherdirection and by a movement of the operators fingers.

22. A portable pneumatic hammer provided with but a single valve, andmeans actuated independently of the valve for holding said valve in theclosed position to stop the hammer; said valve being constructed; andarranged to reciprocate continuously when released and acted upon by thepressure fluid.

23. A portable pneumatic hammer having a single valve, stops, betweenwhich, the valve when released, reciprocates continuously under theinfluence of the pressure fluid; and means for moving one of said stopsto hold the valve against movement under the pressure fluid and therebyarrest the reciprocation of the valve, and stop the action of thehammer.

24. Ina portable pneumatic hammer having a plunger, ports controllingthe plunger, a combined operating and throttle valve, controlling saidports, stops, between which the valve reciprocates, valv controllingports opened and closed by the 'movement of the valve, whereby itrecipro'cates continuously under the pressure fluid, ene of said stopsbeing movable to arrest the valve short whereby the valve is heldstationary-by the pressure fluid andthe hammer isstoppe and the otherstop being mo able to arrest the immanent of the valve in the otherdirection, in position in which it partly opens ports, whereby the theplunger controlling force of the blow is modified.

25. In a portable pneumatic hammer a combined operating and throttleValve adapted to be reciprocated continuously between movable stops bythe pressiire fluid and means mounted in the handle of the tool by meansof which the position of either one of the mo able stops may beinstantly changed during the action of the tool in I such manner as tovary the velocity of-the striking plunger.'

26. In a portable pneumatic-hammer an operating valve adapted to bereciprocated between two movable stops by the pressure fluid; meansactuated independently of said stops for instantly changing the positionof each one of thestops; said means being actuated by the'hand of theoperator.

o! its port opening. position in one direction,

27. In a pneumatic hammer a combinedthrottle and automatic operatingvalve adapted to be reciprocated continuously by the pressure fluidduring the action of the tool; said valve being positioned directlyabove the cylinder in such manner as to reduce to a minimum, the lengthof the ports from the valve to the cylinder. 28. A pneumatic hammerhaving valve Fontrolling ports, a combined automatic op erating andthrottle valve actuated by the pressure which itcpntrols, suppliedthrough said ports and constructed substantially as described to openthe valve controlling ports at the ends of its strokes, and meansarrest- 1 ing the valve before it opens the port at one end-0f itsstroke whereby it is held by the pressure medium and the action of thehammer is stopped. Y-

29. In a portable pneumatic hammer, a

-working cylinder and striking plunger; an

automatic operating valve reciprocated by the pressure fluid, sa d valvebeing con- Strdcted and arranged to vary the rate of fiowof'the'pressurefluid into the cylinder jand also to Vary the rate oftransfer of the fiuid'froin one end of the cylinder to the other; andmeans actuated independently of the valve for enabling the valve toeffect both variationsindependently of each other,

.saidmeans also enabling the valve to act as v a throttle when the toolis not in action.

30. In a portable pneumatic hammer a working cylinder and strikingplunger; an

-- automatic operating valve located directly above the'end of thecylinder and in a position to admit. pressure fluid to the upper endthereof and to transfer it to the lower end thereof; and means actuatedby pressure and pendcntly of the valve, .whereby the throw of the valvecan be instantly changed at the will of the operator While the tool isin action. i

In a portable pneumatic hammer having an voperating valve that isreciprocated by the pressure fluid, means controlled by the fingers ofthe hand that grasps the handle' of the toolwhereby the throw of thevalve can bechanged instantly and independently in either directionwhile the tool is in .use.

'lhe foregoings ecification signed at J ersey City Hudson y,,this 16thday of Feb ru-ary 1906; v

WILLIAM BAXT'ER, JR. In presence ofv two witnesses- RUTHERFORD LAVE,THOMAS P. JOHNs'roN.

